Anatomy of a Virginal: the Jack

N.B.: I am deeply indebted to Mr. Carey Beebe of Carey Beebe Harpsichords Australia for information and insight concerning modern jacks. At his site can be found his own lucid description of the jack mechanism, as well as many photographs of both modern and traditional jacks.


The jacks perform two crucial roles in the virginal: first, a jack plucks the string when a key is depressed, and second, it damps the string to stop the note when the key is released.

Modern jacks are usually made from molded plastic, although some makers offer traditional jacks in hardwood (at increased cost). Installed in each jack is a tongue, an independent piece which rides on a hinge so that it may rock back and forth. And into each tongue is installed a plectrum, the little strip of thin material that actually plucks the string.

One of the great breakthroughs of instrument design must be the simple yet ingenious design of the harpsichord/virginal jack. The trick is that the tongue must hold the plectrum rigidly in place on the way up when the key is depressed, so that the plectrum plucks the string, causing it to vibrate and produce the sound. But at the conclusion of the note, as the jack comes back down to its resting place, the tongue must allow the plectrum to pivot backwards and slip around the string. If this did not happen, after the initial pluck the plectrum would simply come to rest on top of the string and the jack would have to be reset manually before that note could be played again. In such a case, each note could only be played once in each piece; twelve-tone serial music probably would have evolved much earlier in history.



Fortunately for us, someone (no one knows who) figured out that placing a little stop in front of the tongue keeps the tongue immobilized as the jack rides up, holding the plectrum steady in order to pluck the string. On the way back down, the hinge allows the tongue to pivot back out of the way of the string, and then a small spring (this was traditionally made of brass wire, or more usually, hog bristle) attached to the back of the tongue pops it back into place under the string, ready to pluck again. In real time, this whole operation takes only a tiny fraction of a second, allowing a single note to be repeated quite rapidly.

Nowadays the springs, along with most of the rest of the jack, are normally made of the same plastic (usually Delrin) as the rest of the jack, rescuing many thousands of innocent hogs from the cruel practice of annual depilation.

A small felt damper is inserted into a slot in the top of the jack, with the bottom of the felt positioned just above the level of the plectrum. This felt damps the string, stopping the note when the key is released. Since the plectrum and damper are part of the same mechanism, there is no way to lift all the dampers simultaneously, as with a piano damper pedal, and each note ends as soon as its key is released. In terms of practical musical impact, this means that any "smoothing" or "blending" of one note into the next to achieve a legato effect must be done entirely by the fingers; no cheating with the damper pedal. Sicut erat in principio, et nunc, et semper …

The jack pictured here is not from the Zuckermann virginal kit, but from a French-style harpsichord built from a Hubbard kit. It is a little more sophisticated than the old Zuckermann jack, although the modern touches also create some practical problems. The major differences are the tongue stop, the bottom adjustment screw, and the hinge. In the Zuckermann jack, the hinge is dispensed with altogether and the spring takes over its function. This sounds a bit suspect but it works well enough in practice. We will see how it holds up to constant use once the instrument is completed. As you can see in the photos, the tongue stop in the Hubbard jack is actually the end of a small set screw, which allows the projection of the plectrum to be adjusted. While it is a fine idea to be able to control the plectrum projection so conveniently, it also changes the angle of the plectrum from 90 degrees to a more acute angle, which can adversely affect the voicing. In addition, this raises the height of the plectrum, meaning the string is plucked earlier in the keystroke. Ideally, all of the plectra should pluck their strings at the same point in the stroke - otherwise the response of the instrument becomes inconsistent, undermining the precise rhythmic control which is a hallmark of fine harpsichord playing. Finally, the Hubbard jack includes a bottom adjustment screw, allowing the overall height of the jack to be adjusted. Again, it's a nice convenience, but the small screw heads can dig into the end felt on the key levers, wearing through and making it impossible to remove the keyboard without removing all the jacks first. (Remember, a typical large harpsichord can have 189 or more jacks. Removing and then replacing them all can easily add up to an hour to an otherwise quick operation.) The Zuckermann jacks are supplied slightly too long, and the builder simply files them down until their height is correct. If you go too far and file too much off the bottom, you can always use masking tape or glue some felt to the bottom to raise it again. Historically, jacks never had the bottom adjustment screw; it has been theorized (I believe by Frank Hubbard) that screws with sufficiently fine threads were generally unavailable until the 19th century, well after the "golden age" of harpsichord manufacture (approximately 1500-1800).

A brief video of the harpsichord/virginal action will probably make clear its operation more effectively than any number of words. Here is a clip showing a jack plucking a single note. Since it takes only a tiny fraction of a second, it is difficult to show the tongue pivoting backwards on its hinge to allow the plectrum to go around the string on the way down, so I have included a slow-motion replay of this stage of the action at the end. Choose the High Quality (HQ) setting for better video detail.